The present invention relates to systems for monitoring the fuel level in a vehicle. More particularly, the present invention relates to a system for optimizing refueling of a vehicle, reducing refueling fraud, and providing enhanced fuel information.
Vehicles such as tractor-trailer trucks transport enormous amounts of freight around the globe. Each year these trucks travel millions of miles and consume a correspondingly large amount of fuel. Because just one truck can consume tens of thousands of dollars in fuel, fuel costs make up a significant portion of the operating budget of trucking companies.
While fuel costs are significant, the methods used to control and monitor fuel consumption have remained unchanged for many years. Generally, the driver of each truck in a fleet maintains a manual log detailing the amount of fuel purchased, the cost of the fuel, and the mileage traveled between refueling stops. The driver also makes independent decisions on where and how to refuel the truck. Manual methods like these provide some ability to monitor and control fuel consumption, but are subject to variances inevitably introduced by human beings. Drivers may forget to make log entries or enter information incorrectly. Further, drivers are likely to refuel in random ways. Some drivers may refuel when the fuel level reaches one level such as one-quarter of a tank, others when the level reaches some other level such as one-eighth of a tank. Drivers are also unlikely to have current fuel price information at refueling stations along their route. Without this information, fuel is likely to be purchased at a price that is higher than the lowest available price.
Another problem with the manual methods noted above is their reliance on data from analog fuel level sensors. Most analog fuel sensors are electro-mechanical float devices that suffer from at least two deficiencies. First, they must be calibrated to the size of the tank in which they are installed. Second, they often register inaccurate readings due to changes in tank orientation such as might occur on inclines or when the vehicle rides over bumps. Of course, these devices provide only one type of information, a measurement of the percentage of fuel remaining in the tank: such as F, xc2xe, xc2xd; xc2xc, E. Information such as the actual number of gallons remaining or the number of miles until the tank will be empty is not provided.
Accordingly, there is a need to provide a system that monitors fuel consumption, provides fuel consumption information, and makes refueling decisions for the driver to optimize fuel purchasing and consumption.
The present invention provides a system for monitoring fuel consumption and optimizing refueling of a vehicle. The system includes a fuel level sensor designed to be mounted on a fuel tank. The fuel level sensor has a transducer, such as an ultrasonic transducer, for generating a distance signal that represents the distance between the sensor and the surface of the fuel in the fuel tank. A processor is coupled to the transducer, and is programmed to convert the distance signal to a percentage of capacity signal, calculate the volume of fuel within the fuel tank, and create a message that includes information regarding the volume of fuel in the fuel tank.
The processor of the fuel level sensor is coupled to a vehicle information system that may include information buses and modules such as an on-board computer. The vehicle information system provides the processor with various data including the distance traveled by the vehicle. The processor is coupled through a network to a fuel optimization server that calculates an optimal location for refilling the fuel tank using the message created by the fuel level sensor, data provided by the vehicle information system, and information it receives from a fuel-price-by location service, and a dispatch terminal. The fuel optimization server relays the optimal location for refueling to the vehicle information system and a display or computer coupled to the vehicle information system then displays the refueling information to inform the driver when and where to refuel. Other non-fuel related information (such as engine performance data from the J1587 bus) can also be transmitted from the vehicle to the dispatch terminal to allow scheduling of routine maintenance or detection of developing engine problems.
The computing power of the invention permits the generation of numerous other types of fuel-related information. For example, the processor may be programmed to calculate a signal indicative of the number of miles-to-empty (hereinafter xe2x80x9cmiles-to-empty signalxe2x80x9d), and provide that miles-to-empty signal to the dispatch terminal as well as to the vehicle driver. This type of information provides drivers more flexibility to plan refueling stops than standard fuel measurement systems which, in general, merely display the amount of fuel remaining in a tank on an analog gauge mounted in the vehicle.
Another feature of the present invention is that it measures and calculates fuel-related information with a level of accuracy not achieved heretofore. The fuel level sensor used in the system may include a vehicle-speed-dependent filter to reduce the measurement affects of standing waves in the fuel tank caused by vehicle motion. Another interesting feature of the present invention is that it may automatically calculate the size of the fuel tank with which it is used.
Several methods are encompassed by the teachings of the present invention. One of them relates to a method of calculating a miles-to-empty value for a fuel tank in a vehicle. According to the method, a percentage of capacity value is acquired from a fuel level sensor mounted on the fuel tank. A total fuel capacity value that has been preprogrammed into the sensor is retrieved from memory. Alternatively, the sensor calculates a total fuel capacity value. A fuel economy value is then calculated. A fuel remaining value is determined by multiplying the percentage of capacity value by the total fuel capacity value. Finally, a miles-to-empty value is determined by multiplying the fuel remaining value by the fuel economy value. Using other methods of the present invention, a miles-to-empty value may be determined based on the vehicle distance traveled. Still other methods relate to calculating the size of a fuel tank based on the distance traveled by the vehicle or the relative hours of fuel consumption and the fuel flow rate. Additional methods taught by the invention include determining the hours until the tank is empty, identifying a leak in a tank, and identifying refueling fraud.
These and other features of the invention will become apparent upon consideration of the following detailed description and accompanying drawings of the embodiments of the invention described below.